Performance of Beef Replacement Heifers Grazing Three Warm-Season Perennial Grasses

Abstract

Bagley, C.P. 1996. Performance of beef replacement heifers grazing three warm-season perennial grasses. J. Appl. Anim. Res., 9: 33–43.

A study was conducted to compare the performance of beef replacement heifers grazing three warm-season perennial grasses using relatively high levels of N fertilizer. Crossbreed heifers initially 14 mo of age with an average weight of 292 kg were blocked according to breed type and allotted to pastures of common bermudagrass [Cynodon dactylon (L.) Pers.], ‘Alicia’ bermudagrass and ‘Pensacola’ bahiagrass (Paspalum notatum Flugge). All pastures had been established for several years prior to initiation of the grazing trials on Coastal Plain (Agric., Plinthaquic and Plinthic Paleudults) soils. All pastures received 55 kg/ha of N as ammonium nitrate starting 3 wk prior to initial grazing and at 21-d intervals during the grazing period. The “put and take” system of grazing management was utilized with stocking rates adjusted at 3 wk intervals based on forage canopy height. Crude protein and neutral detergent fiber were highest (P>.05) for Alicia bermudagrass, while lignin was highest (P>.05) for bahiagrass during the grazing season. Forage availability (above ground level) of grazed pastures was 1804, 1398 and 1609 kg/ha for common bermudagrass. Alicia bermudagrass and bahiagrass, respectively. Heifers grazing common bermudagrass had higher (P>.05) daily gains (.36 kg/d) than did heifers grazing either Alicia bermudagrass (.20 kg/d) or Pensacola bahiagrass (.19 kg/d). Stocking rates (heifers/ha) were higher (P>0.5) for Alicia pastures compared with common bermudagrass, with bahiagrass pastures being intermediate. The data indicate that stocking rate is highest with Alicia bermudagrass, but animal performance was greatest using common bermudagrass.

Key words:

• Beef cattle
• grazing
• performance
• stocking rate